Processes for fabricating electronic devices containing semiconductors generally include steps in which layers or features of material are deposited or patterned (i.e., etched) within a vacuum chamber, generally called a semiconductor process chamber. The chemical byproducts and unused reagents of such deposition or etch processes are mostly exhausted from the chamber by an exhaust pump, but some residue unavoidably deposits on the chamber wall and on other surfaces within the chamber. Such residue must be cleaned or removed periodically in order to maintain consistent process conditions and to prevent the residue from flaking off and contaminating the electronic device being fabricated.
A conventional method of cleaning residue from the interior surfaces of the chamber is to supply to the chamber interior a gas mixture containing radicals produced by the plasma decomposition of fluorine-containing gas compounds. The plasma may be produced inside the chamber or in a remote plasma source. In particular, such fluorine-containing gas compounds conventionally are used to remove residue containing silicon, silicon oxide, or silicon nitride. Such residue commonly is produced by processes for depositing silicon, silicon oxide, or silicon nitride on a substrate, or by processes for sputter etching or reactive ion etching of such materials on a substrate.
One disadvantage of cleaning processes using such fluorine-containing gas compounds is that such gases are believed to contribute to global warming if they are released to the earth's atmosphere after use. Government regulations are expected to impose increasing restrictions on the use of global warming gases, so there is a need to develop alternative gas chemistries.